Plant Cells, Tissues and Organs Flashcards
Why are plants important?
Produce oxygen for multicellular organisms, allowing them to survive and reproduce.
How is plant growth described? What does this mean?
Modular (growth in modules), reiterative (continuous).
What is determinate growth? Provide examples of plant parts that experience determinate growth.
Determinate development = predictable path and progress, has consistent outcome, specific stop and start times. Example: flowers, most dicot leaves
What is indeterminate growth? Provide examples of plant parts that experience indeterminate growth.
plant will continue adding new organs (leaves, stems, roots) as long as it has access to the necessary resources. Example: stem, roots
What does it mean when we say plants are developmentally adaptive? Provide an example.
When they are injured, they can use stem cells, convert other cells to stem cells and replenish the injured module. Example: all roots can produce new roots.
What are examples of organ systems in plants?
Shoot, root system, flowers
What are examples of plant organs?
lateral roots, stems, leaves
What are simple tissues?
simple tissues contain only one type of cell. The cells are very specialized for their function.
List simple primary tissues in plants and their corresponding cells.
Parenchyma (cells), collenchyma (cells), sclerenchyma (fibers, sclerids), root endodermis (endodermal cells), pericycle (cells).
Is the pericycle cell the same in the xylem and phloem?
pericycle cells have different developmental potential and gene expression in the xylem compared to the phloem.
What cellular components do parenchyma cells have?
Thin primary cell wall (usually unlignified), nucleus, cytoplasm, one (or more)
vacuoles.
What are parenchyma cell walls made of?
cellulose, hemicellulose, pectin
What colour does the primary cell wall of parenchyma typically stain under TBO?
Pink (because of pectin)
What are some functions of the parenchyma?
Photosynthesis, storage, pith, local transport.
What type of cells are present in this image?
Parenchyma
What type of cells are present in this image? (IN centre)
Parenchyma
How do collenchyma cells arise?
Diffrentiated parenchyma cells.
Are collenchyma cells dead or alive at maturity?
Alive.
Describe the cell wall of collenchyma cells and the advantages of its features.
Thickened primary cell wall
*offers more support
Usually not lignified
*Allows for further growth.
What colour to collenchyma cell walls stain under TBO?
Darker pink-purple. (pectin)
What are functions of the collenchyma?
Support, protection.
What type of cells are showcased in this image?
Collenchyma.
Are sclerenchyma cells dead or alive at maturity? Why?
secondary cell wall often takes up most cellular space, which is why it is dead at maturity.
Explain the cell wall of slerenchyma cells.
Thickened primary & secondary cell walls (usually lignified).
What colour do sclerenchyma cells stain under TBO?
Blue/Blue green (lignin)
What are functions of slcerenchyma cells?
Support, protection from microorganisms
Where are the sclerenchyma cells in this image?
Blue ring
Indicate where the phloem, xylem and fibres are located in this image.
A = Xylem
B = fibers
C= phloem
List the complex primary cell tissues
Leaf mesophyll, Xylem, phloem, edpidermis, secretory tissues
What specialized cells make up the leaf mesophyll?
spongy mesophyll cells, palisade mesophyll cells
What specialized cells make up the xylem?
Fibers, parenchyma cells, tracheids, transfer cells, and (mainly in flowering plants) vessel elements.
What specialized cells make up the phloem?
Fibers, parenchyma cells, sclerids, sieve tube members and companion cells in flowering plants or sieve cells and albuminous cells in ferns and gymnosperms, transfer cells.
What specialized cells make up the epidermis?
Shoot and root epidermal cells, trichomes, guard cells, subsidiary cells
What specialized cells make up the secretory tissues?
Transfer cells, secretory cells.
List complex secondary cell tissues.
Secondary xylem, secondary phloem, peridermm
What specialized cells make up the secondary xylem?
Fibers, parenchyma cells, tracheids, vessels members (mainly flowering plants)
What specialized cells make up the secondary phloem?
Fibers, parenchyma cells, sclerids, sieve tube members and companion cells (flowering) or sieve and albuminous cells (ferns, gymnosperms)
What specialized cells make up the periderm?
Cork cells, cork cambium, parenchyma cells.
Exlpain the differences between vessels and tracheids.
tracheids are thinner, can transport high volumes of water. less likely to snap.
vessels are thicker , transport higher volumes but are more susceptible to snapping.
How does the xylem differ from early on in life and at maturity?
Unlignified
& alive initially, highly
lignified & often dead at maturity.
What reflects the function and maturity of the xylem?
Secondary cell wall thickenings.
What do the vascular tissues of the pholoem develop from?
Procambium
What are functions of the phloem?
Transport. Fixed carbon (predominantly sugars),
long distance signaling molecules.
What are sieve elements? Do they have a nucleus?
sieve elements are tubes in which transportation occurs. Do not have nucleus, companion cells help provide them with what they need
How does water move through the phloem?
movement via positive pressure. Movement of sugar drives movement of water.
What is the function of the epidermis?
Protective (biotic and abiotic factors), gas exchange & transpiration (shoot),
secretory, structural.
What are trichomes?
Fine outgrowths on plants; “hair”
Where are apical meristems located? What do they do?
At or near the tips of roots and shoots
Elaborate adult plant
What do lateral meristems do?
Responsible for secondary growth (increases girth)
What type of plants contain intercalary meristems? Provide an example.
Plants without secondary meristems. Monocots
–
Growth of cut grass
What types of primary apical meristems are there? Where are they specified?
Shoot apical meristem (SAM) and root apical meristem (RAM). Specified in embryo.
Identify the SAM and RAm in this image.
Blue = RAM
Red = SAM
How do adventitiuous meristems arise? What does this mean for the plant?
arise spontaneously (ectopically) where we thought we had differentiated tissues; this is why plant growth is so flexible
Why isn’t there secondary growth in monocots?
scattered, closed vascular bundles. They also lack cambium.
How do we explain the longevity and immense heights obtained by wax palms (monocots)?
instead, their vasculature is functional for longer, so they don’t have to keep making them. Can also make new vascular bundles when new leaves are made. Leaves are attached to the trunk, area thickens when leaves fall off.
Parenchyma cells are pluripotent. What does this mean?
they have the ability to
differentiate into other cell types.
Differentiate between the three types of collenchyma cells.
Angular
collenchyma cells have wall thickening in
their corners and stain pink-purple with TBO.
Lacunar collenchyma cells are similar except
that intercellular spaces are still present.
Lamellar collenchyma cells have thickenings
on the inner and outer tangential cell walls
What does xylem tissue do?
main conducting
tissue through which water and minerals are transported from the roots to all plant organs
What is primary xylem developed from? Where is this located?
Developed from procambium of apical meristems in root and shoot tips.
What is primary xylem composed of? When do they form?
Primary xylem is composed of protoxylem, which forms earlier during
plant development, and metaxylem, which forms later after the elongation/expansion of the plant organ is
complete.
Do all plants form secondary xylem?
No, only plants that undergo secondary growth.
What produces secondary xylem?
Vascular cambium.
What does secondary xylem do?
Secondary xylem cells eventually become dead and empty, losing their conducting
functions and serving only to support the plant
What are vessels?
Vessels are long tubes composed of
individual cells, called vessel members,
What are features of vessel members?
thick secondary cell walls and are
opened at each end. May have perforation plate between pairs.
What are tracheids?
Cells with a thick cell wall and
are tapered at the end.
What are ray cells?
Ray cells are
horizontal rows of parenchyma cells that develop from vascular cambium and radiate out from the center
of stems and roots
Describe the cell wall patterns of tracheary elements in the protoxylem and metaxylem.
Tracheary elements that first develop in the protoxylem have
either helical (spiral) or annular secondary wall patterns.
This allows these elements to stretch and elongate.
Treachery elements in the metaxylem have scalariform,
reticulate or pitted secondary cell wall patterns and usually
have ceased elongation
What does phloem tissue do?
Phloem tissue conducts and distributes products of photosynthesis
What are sieve elements? What are their two types?
Sieve elements are the photosynthate conducting cells. They may be either sieve cells
or sieve tube members
What are sieve tubes? What separates them?
Sieve tubes are formed when two or more sieve
elements align end to end, separated by sieve plates allowing for photosynthate movement through
pores.
What are sieve tube members associated with?
companion cells.
What do fibres do in the phloem?
augment structural support of the tissue
What is the shoot system of a plant?
All aboveground portions.
List some functions of the plant shoot.
Respiration, acquiring resources and raw materials, competing for resources, photosynthesis, biotic and abiotic challenges, reproduction and dispersal, growth and development, support, coordination with root system
What is a potential trade-off in functions of plants?
CO2 intake vs. water loss
What organs is the function of support linked to?
Stems
What organs is the function of photosynthesis inked to?
Leaves
What organs is the function of regulating water loss linked to?
Leaves, stem (stomata), cuticle, bark
What organs is the function of reproduction linked to?
Flowers, seeds, fruit, rhizomes, stolons, adventitious meristems
What organs is the function of protection from herbivores linked to?
Defense chemicals, thorns, spines and prickles, trichomes, thick cuticle, woody bark
Label each of these as Determinate (D) or Indeterminate (I) growth:
Shoot growth and root systems of perennial, biennial, annual plants
Crops
Thickening of woody plants
Vascular and cork cambia
Cross-sectional arrangement of tissues and cells in non-woody plant stems
Axillary buds/branches
Individual flowers
Most leaves
Grass leaves
Embryo
Shoot growth and root systems of perennial, biennial, annual plants - I
Crops - D
Thickening of woody plants - I
Vascular and cork cambia - I
Cross-sectional arrangement of tissues and cells in non-woody plant stems - D
Axillary buds/branches - I
Individual flowers - D
Most leaves - D
Grass leaves - I
Embryo - D
What is the procambium?
a meristematic tissue concerned with providing the primary tissues of the vascular system
